1. Field of the Invention
This invention relates to a telephone message recording system. In particular, it relates to one capable of functioning as an automatic telephone message recorder in addition to functioning as a conventional audio system. The total system includes a magnetic playback device known as a double-deck tape recorder consisting of a playback mechanism and a recording mechanism in combination with an adaptor (telephone adaptor) connected to the tape recorder.
2. Background Art
Heretofore, automatic telephone message recording has been effected by coupling an adaptor to a tape recorder as shown in FIG. 1. FIG. 1 shows a portable tape recorder 1 designed to record an audio signal on a magnetic tape contained in a cassette or microcassette for subsequent playback. The tape recorder 1 is combined with an adaptor for connecting the tape recorder 1 to a telephone circuit and control and audio cables 3 and 4, for transmitting control and audio signals.
On receiving a calling signal from the telephone circuit, the adaptor 2 detects the signal and sends a voice synthesizing message, that has been prestored in a built-in solid-state memory, to the telephone circuit. The adaptor 2 short-circuits the control cable 3 after sending out the message. Consequently, a start signal is applied to the start/stop terminal of the tape recorder 1, which was preset to the recording mode, and the tape recorder 1 starts recording by activating the built-in cassette tape. The caller's message transmitted through the telephone circuit is supplied to the microphone terminal of the tape recorder through the audio cable 4 and is recorded on the magnetic tape. The adaptor 2 opens the telephone circuit after a predetermined interval of time subsequent to the detection of the calling signal and also removes the short-circuit from the cable 3. As a consequence, a stop signal is applied to the start/stop terminal, whereby the tape recorder 1 stops the transport of the magnetic tape and is then kept on standby.
Since the conventional telephone message recorder employs a simple portable tape recorder 1 containing a speaker, an amplifier and the like as well as one cassette, the control signal produced by the adaptor 2 is simply intended to start or stop the operation of the recorder. However, most recently developed high-fidelity (HF) audio cassette tape recorders are of the so-called double-deck type including, in combination, a deck at least capable of playback of one tape and another deck at least capable of recording on another tape so that a playback signal from one of the cassettes can be copied onto the other. These double-deck recorders also contain versatile functions including playback by means of a timer in not only the forward direction but also the reverse direction. When the combination of such a double-deck high-fidelity audio tape recorder and an adaptor is used to realize the telephone message recording function, the double-deck recorder must be modified to a large extent in order to prevent malfunction or misoperation. The disadvantage is that such modification makes the recorder complicated on one hand and increases production costs on the other.
In case the listener is seated in a large room and is separated far from the place where the telephone is installed, external noise or the music sound volume may make the user fail to notice an incoming call. In that case, the above automatic telephone message recording system functions as a mere telephone message recorder and is unable to deal with the situation properly.
Another problem is that undesirable trouble, such as the closure of the telephone circuit, readily occurs on arrival of a calling signal because the adaptor 2 is unable to detect malfunctions arising in the tape recorder 1.